gnu: util-linux: Fix CVE-2021-3995 and CVE-2021-3996.

* gnu/packages/patches/util-linux-CVE-2021-3995.patch,
gnu/packages/patches/util-linux-CVE-2021-3996.patch: New files.
* gnu/local.mk (dist_patch_DATA): Add them.
* gnu/packages/linux.scm (util-linux)[replacement]: New field.
(util-linux/fixed): New variable.

1 files changed, 146 insertions, 0 deletions

diff --git a/gnu/packages/patches/util-linux-CVE-2021-3995.patch b/gnu/packages/patches/util-linux-CVE-2021-3995.patch
new file mode 100644
index 0000000000..7faea83801
--- /dev/null
+++ b/gnu/packages/patches/util-linux-CVE-2021-3995.patch
@@ -0,0 +1,146 @@
+Fix CVE-2021-3995:
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3995
+https://seclists.org/oss-sec/2022/q1/66
+
+Patch copied from upstream source repository:
+
+https://github.com/util-linux/util-linux/commit/f3db9bd609494099f0c1b95231c5dfe383346929
+
+From f3db9bd609494099f0c1b95231c5dfe383346929 Mon Sep 17 00:00:00 2001
+From: Karel Zak <[email protected]>
+Date: Wed, 24 Nov 2021 13:53:25 +0100
+Subject: [PATCH] libmount: fix UID check for FUSE umount [CVE-2021-3995]
+
+Improper UID check allows an unprivileged user to unmount FUSE
+filesystems of users with similar UID.
+
+Signed-off-by: Karel Zak <[email protected]>
+---
+ include/strutils.h            |  2 +-
+ libmount/src/context_umount.c | 14 +++---------
+ libmount/src/mountP.h         |  1 +
+ libmount/src/optstr.c         | 42 +++++++++++++++++++++++++++++++++++
+ 4 files changed, 47 insertions(+), 12 deletions(-)
+
+diff --git a/include/strutils.h b/include/strutils.h
+index 6e95707ea..a84d29594 100644
+--- a/include/strutils.h
++++ b/include/strutils.h
+@@ -106,8 +106,8 @@ static inline char *mem2strcpy(char *dest, const void *src, size_t n, size_t nma
+ 	if (n + 1 > nmax)
+ 		n = nmax - 1;
+ 
++	memset(dest, '\0', nmax);
+ 	memcpy(dest, src, n);
+-	dest[nmax-1] = '\0';
+ 	return dest;
+ }
+ 
+diff --git a/libmount/src/context_umount.c b/libmount/src/context_umount.c
+index 173637a15..8773c65ff 100644
+--- a/libmount/src/context_umount.c
++++ b/libmount/src/context_umount.c
+@@ -453,10 +453,7 @@ static int is_fuse_usermount(struct libmnt_context *cxt, int *errsv)
+ 	struct libmnt_ns *ns_old;
+ 	const char *type = mnt_fs_get_fstype(cxt->fs);
+ 	const char *optstr;
+-	char *user_id = NULL;
+-	size_t sz;
+-	uid_t uid;
+-	char uidstr[sizeof(stringify_value(ULONG_MAX))];
++	uid_t uid, entry_uid;
+ 
+ 	*errsv = 0;
+ 
+@@ -473,11 +470,7 @@ static int is_fuse_usermount(struct libmnt_context *cxt, int *errsv)
+ 	optstr = mnt_fs_get_fs_options(cxt->fs);
+ 	if (!optstr)
+ 		return 0;
+-
+-	if (mnt_optstr_get_option(optstr, "user_id", &user_id, &sz) != 0)
+-		return 0;
+-
+-	if (sz == 0 || user_id == NULL)
++	if (mnt_optstr_get_uid(optstr, "user_id", &entry_uid) != 0)
+ 		return 0;
+ 
+ 	/* get current user */
+@@ -494,8 +487,7 @@ static int is_fuse_usermount(struct libmnt_context *cxt, int *errsv)
+ 		return 0;
+ 	}
+ 
+-	snprintf(uidstr, sizeof(uidstr), "%lu", (unsigned long) uid);
+-	return strncmp(user_id, uidstr, sz) == 0;
++	return uid == entry_uid;
+ }
+ 
+ /*
+diff --git a/libmount/src/mountP.h b/libmount/src/mountP.h
+index d43a83541..22442ec55 100644
+--- a/libmount/src/mountP.h
++++ b/libmount/src/mountP.h
+@@ -399,6 +399,7 @@ extern const struct libmnt_optmap *mnt_optmap_get_entry(
+ 			     const struct libmnt_optmap **mapent);
+ 
+ /* optstr.c */
++extern int mnt_optstr_get_uid(const char *optstr, const char *name, uid_t *uid);
+ extern int mnt_optstr_remove_option_at(char **optstr, char *begin, char *end);
+ extern int mnt_optstr_fix_gid(char **optstr, char *value, size_t valsz, char **next);
+ extern int mnt_optstr_fix_uid(char **optstr, char *value, size_t valsz, char **next);
+diff --git a/libmount/src/optstr.c b/libmount/src/optstr.c
+index 921b9318e..16800f571 100644
+--- a/libmount/src/optstr.c
++++ b/libmount/src/optstr.c
+@@ -1076,6 +1076,48 @@ int mnt_optstr_fix_user(char **optstr)
+ 	return rc;
+ }
+ 
++/*
++ * Converts value from @optstr addressed by @name to uid.
++ *
++ * Returns: 0 on success, 1 if not found, <0 on error
++ */
++int mnt_optstr_get_uid(const char *optstr, const char *name, uid_t *uid)
++{
++	char *value = NULL;
++	size_t valsz = 0;
++	char buf[sizeof(stringify_value(UINT64_MAX))];
++	int rc;
++	uint64_t num;
++
++	assert(optstr);
++	assert(name);
++	assert(uid);
++
++	rc = mnt_optstr_get_option(optstr, name, &value, &valsz);
++	if (rc != 0)
++		goto fail;
++
++	if (valsz > sizeof(buf) - 1) {
++		rc = -ERANGE;
++		goto fail;
++	}
++	mem2strcpy(buf, value, valsz, sizeof(buf));
++
++	rc = ul_strtou64(buf, &num, 10);
++	if (rc != 0)
++		goto fail;
++	if (num > ULONG_MAX || (uid_t) num != num) {
++		rc = -ERANGE;
++		goto fail;
++	}
++	*uid = (uid_t) num;
++
++	return 0;
++fail:
++	DBG(UTILS, ul_debug("failed to convert '%s'= to number [rc=%d]", name, rc));
++	return rc;
++}
++
+ /**
+  * mnt_match_options:
+  * @optstr: options string
+-- 
+2.34.0
+